LAMELLAR MACROCRYSTALS OF NASCENT LIQUID-CRYSTAL POLYMERS

Large (up to 0.5 mm) single crystals of two liquid crystalline polymer s, poly(p-oxybenzoate) (PpOBA) and the presumably random copolymer pol y(m-oxybenzoate/2,6-oxynaphthoate) (1/1) [P(mOBA/ONA)], have been grow n by the confined thin film melt polymerization technique at 180-200 d egrees C. These large, thick 'macro' crystals, as well as single discl ination domains, form in regions in which the 'monomer melt' spans the gap between the confining surfaces; when the 'melt' only wets one of the surfaces thin, small crystals and single disclination domains are formed, as reported previously. When reheated to the polymerization te mperature the copolymer disclination domains appear to revert to the l iquid crystal state. The macrocrystals transform at the higher, 275 de grees C d.s.c. measured Tk-m of the copolymer. All of these structures , however, are composed of ca. 100 Angstrom thick lamellae for the gro wth conditions used. FTi.r. microscopy confirms the copolymer nature o f the P(mOBA/ONA) samples. Copyright (C) 1997 Elsevier Science Ltd.